In the present application, the expression "recliner chair" is used in its broadest sense and is meant to include all forms of motion seats capable of reclining, such as, chairs, sofas and loveseats.
Recliner chairs are well known and enjoy widespread usage in the home and office. In general, a recliner chair comprises a stationary base, a movable seat-footrest assembly and a linkage mechanism interconnecting the base and seat-footrest assembly. Most frequently, such recliner chairs are manually operable by the occupant in a variety of well known ways, such as, pushing on the armrests, leaning backward against the backrest, manipulation of a side handle, pressing down with the legs on the extended footrest, or the like. Examples of such recliner chairs may be seen in U.S. Pat. Nos. 3,044,827; 3,433,527; 3,858,932; 3,941,417; and U.S. Pat. No. Re. 29,483.
It is also knwon to automate the operation of recliner chairs with the use of motor drive means. Typically, the motor drive means may comprise an electric motor affixed to the base and having a gear reduction box and power screw output. The free end of the power screw may be connected to a portion of the linkage mechanism or seat assembly so that rotation of the screw causes motion, extension and/or retraction, of the seat-footrest assembly.
Understandably, the use of motorized power screw drives to operate recliner chairs provides a number of advantages. For example, the chair occupant is no longer required to exert physical force to operate the chair. Also the motor drive can be stopped at will to retain the seat at any intermediate position between full upright and full recline, an operation not generally achievable with a manually operated linkage mechanism which typically provides only two or three fixed balance points. However, it has now been recognized that a purely motorized recliner chair can give rise to certain problematic or serious situations.
Those skilled in the art will appreciate that a practical power screw drive operates at a reduced rate of rotation which is usually provided by gear reduction means. As a result, the movements of a motorized chair are considerably slower than those of a manually operated chair. Emergency situations frequently occur which dictate that the chair occupant arise from the chair as quickly as possible. For example, a doorbell, a child's cry, the ringing of a telephone, or the like, would dictate prompt return of the chair to the upright position with the speed that can be obtained only by manual operation.
Another situation which could occur is the malfunction of the motor or loss of electric power. Under those conditions, it is quite difficult, and even dangerous, for an occupant to try and get out of a chair which is in the recline position.
There thus exists a need for a motorized recliner chair having means for selectively decoupling the motor drive to convert the chair to manual operation. The decoupling means should be substantially fail-safe, simple to operate and add little if any to the total cost of the chair.